One type of dental implant typically is cylindrical in shape with an outer diameter of between about 4 and 5 millimeters, and is inserted to a fixed depth into the alveolar bone of the maxilla (upper jaw). For patients with an alveolar bone thickness of more than about 5 millimeters, this type of implant may be secured in a relatively stable manner. However, for patients with less than 5 millimeter alveolar bone thickness, dental surgeons use a procedure known as sinus lift bone augmentation to build up the thickness of the alveolar bone of the maxilla, so that dental implants may be securely installed therein.
As shown in FIG. 1, prior sinus lift bone augmentation procedure requires that the side wall bone of the maxillary sinus cavity be broken and a hole opened therein. The sinus cavity membrane is separated from the upper surface of the maxilla, and an elevator material made of a mixture of bone material and blood serum is inserted through the hole in the side of the maxilla and placed at the bottom of the sinus cavity between the maxilla and the sinus lining. The elevator material hardens over time to increase the effective thickness of the maxilla, thereby providing additional stability for the implant.
While this prior sinus lift bone augmentation procedure may be effective when performed by highly skilled surgeons, it nonetheless involves several inherent risks. First, exposure of the bone when the side wall of the sinus cavity is broken creates the risk of infection. Second, breaking the bone in the side wall or bottom of the sinus cavity creates a risk of penetration of the membrane lining the sinus cavity, which can further result in infection. Finally, during installation of the elevator material and implant itself, it is difficult to judge the amount of elevator material and depth of implant penetration into the sinus cavity, creating a risk that insufficient filler has been added, which, could weaken the implant, or a risk of overpenetration by the elevator material or implant, which could damage the sinus membrane. If the sinus membrane is ruptured, the transplanted elevator material may become infected. Further, this complicated procedure may involve hospitalization of the patient, which is time consuming and expensive.
It is also known to punch through from a tooth socket into the maxillary sinus cavity using a circular instrument as illustrated in FIG. 2. The instrument is then removed to form a hole in which an implant may be fastened. However, when using this procedure, it is difficult to determine whether the lower portion of the maxillary sinus cavity can be safely lifted up without fracture of the alveolar bone and the bottom of the sinus cavity wall. Therefore, success of this procedure is greatly dependent upon the skill of the dental surgeon performing the operation.